1. Field of the Invention
The present invention relates to a packaging method of a semiconductor device and a packaging structure thereof, particularly to a packaging method of a light-sensing semiconductor device and a packaging structure thereof, which can protect a light-sensing chip from the pollution by external particles.
2. Description of the Related Art
In a light-sensing semiconductor, the light-sensing region of the light-sensing chip is used to acquire images; thus, the quality of the light-sensing semiconductor correlates closely with the light-sensing chip. During the packaging process of the light-sensing chip, the chip is often polluted by particles; therefore, packaging is a critical process for the quality of the light-sensing semiconductor.
Refer to FIG. 1A and FIG. 1B section views schematically showing the steps of the conventional packaging method of a light-sensing semiconductor device. A light-sensing wafer 10 has multiple light-sensing chips 12, and each light-sensing chip 12 has a light-sensing region 14. A light transparent cover 16 has a matrix of spacer walls 18; an adhesive 20 is applied to between the spacer walls 18, as shown in FIG. 1A. Then, the light transparent cover 16 is flipped and put onto the light-sensing wafer 10, as shown in FIG. 1B. Thus, the light-sensing region 14, the spacer walls 18 and the light transparent cover 16 enclose an airtight space, which can protect the light-sensing region 14 of the light-sensing chip 12 from the pollution by external particles.
As the adhesive 20 has been applied to the light transparent cover 16 when the light transparent cover 16 is being flipped to put onto the light-sensing wafer 10, the adhesive 20 may drops onto the light-sensing region 14 of the light-sensing chip 12, which pollutes the light-sensing region 14 and influences the quality and yield. Further, as the light transparent cover 16 is flipped and then aligned to join with the light-sensing wafer 10, this conventional packaging method has the problem of alignment accuracy. Furthermore, during the press-joining step, if the adhesive is applied too much, the adhesive will overflow into the light-sensing region 14 and pollute the light-sensing chips 12. If the adhesive is applied too little, the sealing effect is poor.
Accordingly, the present invention proposes a packaging method of a semiconductor device and a packaging structure thereof to protect the light-sensing chip from the pollution by external particles.